Parachute with destructive agent dispensing means



y 28, 1970 R. E. AINSLIE 3,521,840

PARACHUTE WITH DESTRUCTIVE AGENT DISPENSING MEANS Filed Nov. 27. 1968 2 Shets-Sheet 1 Fig. 1

ROBERT E. AINSLIE BY L ATTQMEYJ y 1970 R. E. AINSLIE 3,521,840

PARACHUTE WITH DESTRUCTIVE AGENT DISPENSING MEANS Filed Nov. 27. 1968 2 sheets-sheet a INVENTOR.

ROBERT v E. AINSLIE BY m United States Patent 3,521,840 PARACHUTE WITH DESTRUCTIVE AGENT DISPENSING MEANS Robert E. Ainslie, Glenside, Pa., assignor to the United States of America as represented by the Secretary of the Navy Filed Nov. 27, 1968, Ser. No. 779,328 Int. Cl. B6411 17/00 US. Cl. 244-142 19 Claims ABSTRACT OF THE DISCLOSURE STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION Aerial delivery of pay loads into enemy territory is often rendered less effective when indicia of delivery can be detected as by observing particularly from the air a parachute which may have become entangled in trees. The use of camouflaged parachute material, while reducing the probability of visual detection, is not entirely effective in that the sheen of the camouflaged fabric breaks the irregular motif presented by the adjacent vegetation. Apart from the time factor, parachute re covery is generally untenable in that there may be ground based personnel nearby, in that the degree of parachute entanglement in the trees can be severe, and in that finding the parachute from the ground, particularly Where the chute is entangled high above ground level, can be difficult and virtually impossible at night. Therefore, it is desirable that there be provided automatically actuated means which destroys the parachute fabric and, yet, does not interfere with the safe delivery of the pay load.

SUMMARY OF THE INVENTION This invention generally relates to parachutes and means for destroying parachutes and, more particularly, to pyrotechnic devices for dispensing a fabric-destructive agent.

It is the general purpose of this invention to provide a parachute having automatic parachute destroying means which is small and does not interfere with the normal delivery function of the parachute. More particularly, it is contemplated that the destroying means include a dispenser which is actuatable during parachute descent to ensure optimum distribution of a fabric-destroying agent. Briefly, the general purpose of the invention may be accomplished by providing an automatic dispenser arranged to direct a fabric-destructive agent on the parachute. More particularly, it is contemplated that the dispenser be actuated after full deployment of the parachute and, further, that the dispenser include a nozzle arranged adjacent the parachute for spraying the interior side of the fabric of the deployed parachute with the fabric destroying agent.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents a side view of a first embodiment of the invention with portions of a fully deployed parachute broken away;

FIG. 2 represents a side view of a second embodiment of the invention;

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FIG. 3 represents a view in longitudinal cross section of the dispenser of FIG. 1;

FIG. 4 represents a view of the dispenser in cross section taken generally along line 44 of FIG. 3; and

FIG. 5 represents a diagram of the deployment of a parachute according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, the invention provides an auto-destructive parachute system including a parachute of any type such as a conventional canopy-type parachute 10 shown fully deployed during descent in FIG. 1 and a dispenser 11 connected to the parachute 10 and shown as dispensing a fabric-destructive agent 12 on the parachute .10. In order to minimize wasting the destructive agent as may occur in strong cross-wind situations, it is desirable that the dispenser 11 be positioned as shown in FIG. 1 near the main vent 15 of the parachute 10 so that the agent 12 may be more probably uniformly distributed over the interior periphery of the parachute 10.

It is contemplated that a dispenser such as a spray device 11 can be connected to the point of confluence of the suspension lines 13' of a parachute 10 as shown in the embodiment of FIG. 2 or carried by the pay load .14 being delivered. The spray device 11 is actuated by a lanyard upon parachute deployment to direct a spray of a fabric-destructive agent such as acid upwardly toward the descending parachute 10'.

The advantages of positioning the spray device 11 on the axis A extending between the center of the parachute and the point of confluence of the suspension lines 13 near the peak or the main vent 15 can become more apparent by reference to the air flow currents generally present during parachute descent and indicated in FIG. 1. For example, some air such as indicated by flow lines a is forced outwardly under the skirt 16 of the parachute 10. Other air flow currents indicated by the flow lines b extend through the fabric of the parachute 10 itself. Still other flow currents indicated by the lines 0 are directed through the main vent 15 of the parachute 10.

The foregoing air flow pattern within the parachute 10 may be used to advantage in establishing a spray pattern for the dispenser 11. For example, the dispenser may be arranged and constructed to direct a spray of the agent through a plurality of substantially contiguous zones such as X, Y, and Z which are bounded by generally conical surfaces extending from the nozzle 20 of the dispenser 11. The uppermost boundary of the zone Z may be established slightly outwardly of the inner periphery of the vent 15 so that the flow lines 0 can assist in dispersing the fabric-destructive agent on the parachute fabric immediately adjacent the main vent 15. Similarly, the lower boundary of the zone X need not be directed beyond the skirt 16 for the flow lines a assist in dispersing some of the agent 12 from the dispenser 11 over the inner periphery of the skirt 16 with suflicient concentration to cause its subsequent disintegration.

Referring now to FIG. 3, the dispenser 11, more particularly, includes a tube 21 of circular cross section closed at one end by the nozzle generally indicated at 20 and at the other end by a cylindrical breechblock 23. The breechblock 23 includes a threaded coaxial bore 24 extending inwardly of the outer end of the block 23 and communicating with a smaller diametered, recessed coaxial bore 25 which is sized to receive the pyrotechnic cartridge 26 preferably of the delayed-firing type. A conventional mechanical cartridge-actuating device 27 provided with a safety pin 28 is threaded into the bore 24 and includes a removable sear pin 29 having a transversely extending aperture 30 formed for connection to a lanyard 31 which is used to remove the pin 29 and 3 thereby cause actuation of the device 27. The safety pin 28 is removed after attaching the loaded dispenser to the parachute 10, as is hereinafter explained, and just prior to packing the parachute for use. The inner end of the breechblock 23 terminates in a coaxially extending boss 32 which is receivable within a correspondingly sized recess 33 formed in a cylindrical piston 34. In order to prevent leakage of the fabric-destructive agent 12 which is contained in liquid form between the piston 34 and the nozzle 20, both the piston 34 and the breechblock 23 include annular grooves 35 which extend about their lateral peripheries and which are formed for receiving annular O-rings 36 of a flexible, elastic material which can withstand the corrosive effects of the particular fabric-destructive agent 12 being employed. The piston 34, tube 21, and breechblock 23 are made of a tough, strong, corrosion resistant material such as stainless steel.

The breechblock end of the tube also includes slidably received thereover a sleeve 38 having a radially projecting flange 39 including a circular arrangement of typing apertures 40 through which is interlaced a cord 41 attaching the dispenser 11 to the parachute 10 within and centrally of the main vent 15. The flange 39 is located along the length of the tube 21 so that the nozzle 20 will be arranged within the parachute contained in the optimum spraying position relative to the fully deployed parachute 10. Three peripherally-spaced screws such as 42, secure the flanged sleeve 38 and the tube 21 to the breechblock 23 so that the breechblock 23 closes the end of the tube 21 in a sealing engagement and so that the piston 34 is movable within the tube 21 away from the boss 32 by explosive gases generated upon delayed detonation of the cartridge 26 after actuation by the device 27.

The nozzle 20* is connected to the tube 21 through a coaxially threaded ring member 45 having an encircling annular O-ring 46 received in a groove 47, having an annular crimping groove 48 and being crimped within the end of the tube 21 to form a fluid-tight seal. The nozzle 20 includes a generally cylindrical, valved coupling member 50 also conveniently made of stainless steel, having a boss 51 threaded into the ring member 45 and having an intermediate, external flange 52 seated against the outer face of the ring member 45. An annular O-ring 53 received in an annular groove 53 extending about the periphery of the boss 51 adjacent the flange 52 assures a fluid-tight seal between the nozzle 20 and the ring member 45. The coupling member 50 further includes a recessed, coaxial, cylindrical cavity 55 extending thereinto through the boss 51. The outer end of the cavity 55 extends inwardly from a larger diametered, annular recess 56 within which is force fit a plug bushing 57 having a coaxial agent influx orifice 58 formed for receiving a force fit plug 59. The plug 59 has a plurality of spaced apart, externally radiating, annular projections 60 forming a labyrinth seal and is formed of a plastic material such as Teflon which resists corrosion by the agent 12. The cavity 55 is sized to receive the plug 59 therewithin, when the plug 59 is forced through the bushing 57 upon an increase in internal tube pressure to a level such as 30 to 50 psi. caused by detonation of the cartridge 26. As shown in FIG. 4, a circular arrangement of longitudinally extending, agent efilux orifices 61 communicating with the internal cavity 55 is formed in the other end of the member '50 to encircle a coaxial boss 62 projecting therefrom.

The protruding end of the coupling member 50 is chamfered as at 63 outwardly of the orifices 61 at an angle K, as shown in FIG. 3, to control the upper boundary of divergence of the zone Z of the spray pattern of the dispenser 11. In order to further control the desired spray pattern, the nozzle 20 includes a coaxially aligned pair of concave-convex, conical nozzle elements 64 and 65 having opposed convex surfaces 66 and having a circularly arranged plurality of orifices 67 aligned for registration with the orifices 61 of the member 50. The concave and convex surfaces, 68 and 66, of the nozzle ele ments 64 and 65 form a peripheral spray-diverting flange 69 whose concave surfaces 68 and convex surfaces 66 respectively diverge at angles L and M from planes extending normal to the axis n of the nozzle 20. The elements 64 and 65 further include abutting bosses 70 projecting coaxially from the convex side thereof to perform an element spacing function. The nozzle 20 further includes a coaxially located, truncated conical nozzle element 73 whose conical surface 74 diverging at an angle N from a plane normal to the nozzle axis n also functions as a spray deflecting surface. The element 73 also has an element spacing boss 75 projecting coaxially of the conical surface 74 and abutting the outer nozzle element 65.

The nozzle elements 64, 65 and 73 are secured to the coupling member 50 by a flanged eyebolt 77 which is coaxially threaded therethrough and into the coupling member 56. The eyebolt 77 provides a tying point for a dispenser stabilization lanyard 79, shown in FIG. 3, whose other end is connected to the point of confluence of the suspension lines 13 of the parachute 10.

The bosses 62, 70 and '75 which are interposed between the coupling member 50 and the elements 64, 65 and 73 have lengths set to achieve optimum droplet size for the agent 12 in the spray being generated. The diameters of the orifices 61 and 67 also affect droplet sizes. For example, if the spacings between the nozzle elements 64, 65 and 73 are increased, larger droplets are formed. Additionally, the respective spacings between the elements 64, 65 and 73 and the member 50 affect the amounts of agent 12 which are diverted therebetween and thus control the spray density in each of the three spray zones X, Y and Z. For a conventionally configured canopy parachute angles K, L, M, and N respectively of 30, 5, 15 and 30 degrees, efliux orifice diameters of eighty-six thousandths inch and spacings between the member 50 and the element 64 of thirty-eight thousandths inch, between the elements 64 and 65 of thirty-six thousandths inch, and between the elements 65 and 73 of twenty-four thou sandths inch enable the provision of a substantially uniformly dense spray of the agent 12 to the entire inner periphery of the parachute 10.

Prior to interlacing the dispenser 11 to the parachute 10 and packing the parachute 10, the coupling member 50 is unscrewed from the member 45, and tube 2-1 of the dispenser 11 is filled with the fabric-destroying agent 12. Many acid and caustic solutions are suitable for use. A concentrated solution of sulfuric acid comprising ten volumes of 98% H 804 and one volume of H 0 has been found to affect fabric disintegration approximately thirty seconds after spray application. The above-noted sulfuric acid solution also has a minimal freezing point which assures proper operation of the dispenser 11 even after exposure to the low temperatures at high altitudes. The small time delay is desirable in order that the parachute 10 maintain its structural integrity until after landing he pay load I14. The degree of concentration and the type of solution can, of course, be varied in order to effect the desired degree of delay in destroying the parachute 10 after application. The appropriate volume of solution to be contained within the tube 21 depends upon the amount of fabric to be destroyed and is most easily determined by experimentation with the parachutes of the desired size. For example, 44 cc. of the above-described sulfuric acid solution has been found to be a satisfactory amount for substantially destroying all of the fabric in a canopy parachute of a constructed diameter of about 92 inches, leaving behind only the suspension lines and the webbing and reinforced areas. The portion of a camouflaged parachute remaining after fabric disintegration tends to blend in well with the adjacent vegetation, making visual detection a remote possibility.

It is contemplated that the dispenser 11 be actuated in response to deloyment of the main parachute 10. For example, in FIG. 5, a pilot parachute has withdrawn the bag 91 within which was contained the main parachute 10. The lanyard 31 is connected between the bag 91 and the sear pin 29 of the dispenser 11 so that when the bag 91 is removed by the pilot parachute 10, as when a line reefer (not shown) is actuated, the sear pin 29 is withdrawn from the cartridge actuator 27 initiating detonation of the cartridge 26. The cartridge 26 is preferably of a delay type which explodes a short interval of time after actuation. For example, a time period of three seconds was found sufiicient to allow the main parachute to fully deploy, the canopy oscillations incidental to deployment being substantially damped out.

The dispenser stabilization lanyard 79 maintains the orientation of dispenser 11 and its nozzle 20 relative to the deployed parachute 10 so that the agent 12 is uniformly dispersed on the interior of the parachute 10 even though the parachute 10 may nutate or laterally oscillate during descent. Alternative stabilization measures such as lines extending from the nozzle 20 to the skirt 16 of the parachute 10'are also contemplated.

When the cartridge 26 is detonated, the piston 34 applies pressure through the agent 12 to the plug 59 which is forced through the bushing 57 into the internal cavity 55 of the coupling member 50. Thereupon the agent 12 is forced by the increased pressure through the coupling member 50 and the orifices 61 and 67 and is diverted by the elements 64, 65 and 73 to form the spray pattern.

It is contemplated, of course, that the deployment of the main parachute 10 could be delayed as by actuating a conventional reefing line cutter .(not shown) after a period of time allowing descent from a high altitude where the system is launched to a lower altitude. When the reefing line cutter (not shown) is actuated at the lower altitude to allow the pilot parachute 90 to withdraw the main parachute bag 91 and free the main parachute 10 for deployment, the lanyard 31, which is attached to the main bag 91, removes the sear pin 29 and actuates the device 27 to fire the cartridge 26. Full deployment of the main parachute 10 occurs first after which the spraying of the parachute 10 with the agent 12 takes place. Thereby, the fabric of the parachute 10 is uniformly sprayed and is not disintegrated prior to the anticipiated time period for descent to a landing.

The invention provides a self-destructive parachute which includes a simply manufactured, inexpensive dispenser for a fabric-destructive agent which dispenser is actuated in response to main parachute deployment after a delay allowing full deployment. The invention assures that the structural integrity of the parachute will be maintained until after a landing of its pay load has been accomplished. The parachute system apparatus of the invention may be also used for the delivery of personnel wherein it is desired that the parachute be destroyed shortly after landing such as to reduce the time and efiort for hiding the parachute. Additionally, the invention provides an optimum spray nozzle and dispensing device for destroying parachutes particularly of the canopy type.

Obviously many modifications and variations of the present invention are possible in view of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. Apparatus comprising:

a parachute;

a flowable material having chemical properties capable of destroying said parachute when physically exposed thereto; and

dispenser means containing said material and arranged for dispensing said material onto said parachute, said dispenser means includes nozzle means formed for directing said material exclusively toward the inner periphery of said parachute in a fully deployed condition.

2. Apparatus according to claim 1 wherein:

said parachute includes suspension lines connected together at a point of confluence; and

said dispenser is connected to said parachute for arrangement adjacent said point of confluence.

3. Apparatus according to claim 1 wherein:

said dispenser is connected to said parachute for arrangement adjacent the center of said parachute in a fully deployed condition.

4. Apparatus according to claim 3 wherein:

said parachute includes a main vent formed therein;

and

said dispenser means is connected to said parachute adjacent said main vent.

5. Apparatus according to claim 1 wherein:

said dispenser means includes actuating means responsive to deployment of said parachute for actuating dispensing said material on said parachute material.

6. Apparatus according to claim 5 wherein said actuating means includes:

means having a removable pin for actuating dispensing said material; and

means connected for removing said pin in response to deployment of said parachute.

7. Apparatus according to claim 5 further comprising:

dispenser stabilizing means connected between said dis-' penser means and said parachute for maintaining said dispenser means in a predetermined orientation relative to said parachute in a fully deployed condition.

8. Apparatus according to claim 1 wherein:

said dispenser means includes actuating means responsive to deployment of said parachute for actuating the dispensing of said material onto said parachute after a predetermined delay.

9. Apparatus according to claim 1 wherein said dispenser means comprises:

a tube for containing a quantity of said material intermediate its ends;

means connected for closing one end of said tube including a coupling member and material dispensing nozzle, said coupling member having a plug for blocking communication between the interior of said tube and said nozzle, said plug being movable in response to increased internal pressure in said tube to permit the flow of said material from said tube and through said nozzle; and

means connected for closing the other end of said tube including pressure generating means for increasing the Internal pressure in said tube.

10. Apparatus according to claim 9 wherein said pres sure generating means includes:

a piston movable within said tube, said material being interposed between said piston and said nozzle means; and

gas generating means for moving said piston toward said nozzle means.

11. Apparatus according to claim 10 wherein:

said coupling member has formed therewithin a plugreceiving orifice communicating with the interior of said tube, an internal cavity communicating with said plug-receiving orifice and sized for receiving said plug and at least one material outflow orifice providing communication between said cavity and said nozzle; and

said plug closes said plug-receiving orifice and is movable into said cavity to establish communication between said cavity and said tube interior in response to increased pressure in said tube interior. 2

12. Apparatus according to claim 11 wherein:

said plug has a plurality of spaced apart annular grooves formed in its orifice engaged periphery for establishing a labyrinth seal, said plug being forced into said plug-receiving orifice from the tube adjacent end thereof.

13. Apparatus according to claim 11 wherein said gas generating means comprises:

a breechblock formed for sealing said other end of said tube, having a boss projecting into said tube interior and having formed therein a cartridge bore sized for receiving a pyrotechnic cartridge and communicating with said tube interior through said boss; and

cartridge actuating means removably attached to said block for closing said cartridge bore;

said piston having a recess formed therein for receiving said breechblock boss.

14. Apparatus according to claim 13 further comprising:

a delayed action, pyrotechnic cartridge received within said cartridge bore for delaying material dispensing a predetermined time after actuation by said cartridge actuating means.

15. Apparatus according to claim 13 further comprismg:

an internally threaded ring member connected in sealing engagement with said one end of said tube;

said coupling member being threadedly connected to said ring member.

16. Apparatus according to claim 11 wherein said coupling member has a projecting boss encircled by a plurality of said material outflow orifices communicating with said cavity; and said nozzle comprises:

a pair of circular discs having abutting bosses coaxially aligned with said boss of said coupling member, said discs having diverging peripheral flanges and an arrangement of orifices extending therethrough encircling said abutting bosses in registry with said material outflow orifices of said coupling member;

a truncated conical member having a boss projecting from its smaller diametered end toward engagement with the outer of said discs and coaxially aligned With said abutting bosses; and

bolt means coaxially connecting said conical member and said disc members to said coupling member.

17. Apparatus according to claim 16 wherein:

said parachute includes a main vent and a plurality of suspension lines connected together at a point of confluence;

said apparatus includes a radially extending flange connected to said tube intermediate its ends, said flange being interlaced to said parachute locating said dispenser means centrally of said main vent with said nozzle projecting toward said point of confluence; and

said apparatus includes a lanyard interconnecting said bolt means and said point of confluence for maintaining nozzle orientation when said parachute is fully deployed.

18. Apparatus according to claim 17 wherein:

the opposed surfaces of said diverging disc flanges are oriented to direct an annular first pattern of said ma terial dispensing radially of said nozzle;

the surface of said disc flange confronting said coupling member is oriented to divert an annular second pattern of said material dispensing on one side of said first pattern adjacent and inwardly of the periphery of said main vent; and

the conical surface of said conical member and the confronting surface of the adjacent said diverging disc flange are oriented to direct an annular third pattern of said material dispensing on the other side of said first pattern inwardly of the outermost periphery of said parachute in a fully deployed condition.

19. Apparatus according to claim 18 wherein:

said conical surface of said conical member bears an angle of 30 degrees relative to a plane passing perpendicularly of the axis of said nozzle;

said projecting end of said coupling member is chamfered outwardly of said circular arrangement of said material outflow orifices;

said diverging disc flanges have opposed surfaces diverging at angles of five degrees relative to said plane and have obverse surfaces diverging at angles of fifteen degrees relative to said plane.

References Cited UNITED STATES PATENTS 12/1947 McKay et al 244-142 X 5/1966 Chappell 244-149 X 

